what will affect the performance of the liquid ring pump
In liquid ring vacuum pumpsare easy to get because of the water, cheap, not high viscosity (and thus less power loss), non-corrosive to the pump, and the general effect of any chemical used for air suction or pressure feed media does not occur, and water on the environment and no pollution, etc., it is generally water as the liquid ring. However, in some chemical process where the use of liquid ring pumps, are often not water as the liquid ring. For example, in the transportation of chlorine chemical plants, due to moisture after chlorine, the metal has a strong corrosive effect, it is not water as liquid ring, but must use any chemical reaction with chlorine does not occur, the pump itself is not corrosive liquids, such as with concentrated sulfuric acid (> 91%) as a liquid ring to transport chlorine.
Performance data liquid ring pumps, are drawn from the water for testing. Design, usually with water as the working medium to design. If the chemical process needed to switch to other liquids as liquid ring, then the performance of the pump with liquid ring will different types of change. This change depends mainly dry saturated vapor pressure of the liquid, severe and viscosity.
First, saturated vapor pressure
Since the liquid ring vacuum pumpis sufficiently agitated, pump chamber relative humidity can be considered as 100%. The theoretical limit of the liquid ring pump vacuum (ie without considering the loss of ultimate vacuum) depends on the saturated vapor pressure of the liquid ring, or that is the theoretical limit of the vacuum pressure of saturated vapor pressure of the liquid ring pump. Visible, the lower the saturated vapor pressure liquid ring vacuum of the theoretical limit of the pump is higher. If the isothermal efficiency unchanged, the actual ultimate vacuum pump is higher. Selection of saturated vapor pressure of the liquid for liquid ring, can improve the ultimate vacuum pump.
The size of the saturated vapor pressure of the liquid in addition to the types of related, but also related to the temperature of the liquid, the lower the temperature, the lower the saturation vapor pressure, the theoretical limits of the pump higher degree of vacuum, and therefore, should be reduced as much as possible of the liquid ring temperature.
1, the impact on the critical pressure
The compressor, the discharge pressure increases with the critical liquid ring severe increase of the vacuum pump, the suction pressure increases with the critical liquid ring severe decreases.
2, on the maximum discharge pressure
Maximum discharge pressure of the water ring compressor with liquid ring increases severe increases. That is, for the same compressors, is inversely proportional to the square root of the maximum discharge pressure reaches the desired speed and leaves reincarnation week liquid ring severe.
3, on the maximum degree of vacuum
With the increase of the liquid ring severe, maximum vacuum of water ring vacuum pump also will increase, proportional to the maximum degree and liquid ring vacuum severe.
4, friction loss on the disk
Power and liquid ring severe friction loss is proportional to the disc.
5, on the sealing performance
Leakage of gas is directly proportional to the square root of the liquid ring severe.
6, the impact on the air amount
Amount of gas leakage increases with the liquid ring severe increases, the actual volume of the pump also increases with severe and decreased.
7, on shaft power
Energy of the liquid ring increase as severe increases, and thus the shaft power required for a corresponding increase.
Third, the viscosity
The viscosity of the liquid ring pump gas impact is small. The main impact of the loss of viscosity of the pump power and, therefore, affect the efficiency of the pump. This size of the impact depends on the Reynolds number Re liquid ring (liquid flow state identification number). An increase in the viscosity of the liquid ring, the Reynolds number is reduced, the Reynolds number, the smaller the difference between the liquid ring pump with water ring pumps it gets.
The viscosity of the liquid ring pump characteristics affect mainly:
1, hydraulic loss
2, the disc friction loss
3, in the same conditions, the Reynolds number is smaller than the large pump to pump large, so the size of the pump also have different effects on the performance of liquid ring pumps of the same viscosity.
4, the impact of viscosity on the pump characteristics tuck loop is also concerned with the speed.
5. The impact on the amount of liquid ring: the viscosity of the liquid ring pump along the wall to form a larger flow boundary layer, there has been tangential dry Shakti in the boundary layer, which prevents the flow along the wall and pump vanes flow, the formation of a large velocity gradient, the motion of liquid ring formation resistance, resulting in reduced liquid ring velocity, reducing the amount of the liquid ring, the degree of increase in dry liquid ring increases with decreases, the amount of the liquid ring liquid ring can reduce the mean blocking is reduced.
6, the impact of temperature on the viscosity of the liquid ring: a liquid ring power loss increases with the degree of twist increases, this loss of power. Most are converted into heat, the temperature of the pump. Therefore, liquid ring pump operation temperature increases with increasing viscosity liquid ring. After the liquid ring temperature increases, the viscosity decreases, helps to reduce the shaft power. Since the temperature rise tuck loops can significantly decrease the degree of vacuum, but also on the change in the power. Therefore, the use of the viscosity of the liquid ring pump should be noted cooling, holding isothermal compression pump.All of the affect can be avoided if you can use the liquid ring vacuum pump correctly